Many views on screening

A mammographer at University of Chicago Hospitals in Chicago gives an annual mammogram to a patient

A mammographer at University of Chicago Hospitals in Chicago gives an annual mammogram to a patient (Nancy Stone, Chicago Tribune)

Alexia Elejalde-Ruiz, Tribune Newspapers

Women with no history of breast cancer have to muddle through conflicting recommendations from medical and advocacy groups on when, how and how often to screen for tumors, as the efficacy of routine mammograms continues to raise hot debate.

The U.S. Preventive Services Task Force, an independent advisory panel appointed by the government, sticks by its controversial 2009 decision to recommend mammograms every two years for women ages 50 to 74, though women who wish to start before then can talk to their doctor about it. The panel also advises doctors against teaching patients how to examine their own breasts.

But several other organizations — including the American Cancer Society, the American College of Obstetricians and Gynecologists and the National Comprehensive Cancer Network — recommend that women at normal risk for breast cancer get an yearly mammogram and annual clinical breast exam starting at age 40.

For women 20 through 39, these groups say, clinical breast exams should be performed every one to three years, and breast self-exams are optional for women starting at age 20, though everyone should be breast-aware and report changes to their doctor.

The National Cancer Institute, part of the National Institutes of Health, recommends mammograms every one to two years for women older than 40. It has no recommendations for clinical breast exams or self-exams.

Meanwhile, the National Breast Cancer Coalition, a grass-roots advocacy group, believes there is "insufficient evidence to recommend for or against universal screening mammography in any age group of women," and "the decision to undergo screening for asymptomatic women must be made on an individual level based on a woman's personal preferences, family history and risk factors."

The debate about mammograms revolves around whether screenings do more harm than good among women younger than 50, who are more likely to have false positives and overtreatment of cancers that would never cause symptoms or threaten a woman's life. Mammograms also are more likely to miss cancer in younger women because their breast tissue is more dense, making tumors harder to spot.

In women with the densest breasts, mammography can miss half of cancers later found on ultrasound, according to a 2002 report in the journal Radiology that reviewed screening sessions performed on more than 11,000 women.

The screening guidelines change for women considered at high risk for breast cancer, which means their lifetime risk of getting breast cancer is greater than 20 percent. Among the factors that can contribute to being high risk are having a BRCA1 or BRCA2 genetic mutation or having a first-degree relative with that genetic mutation; having had radiation therapy to your chest between ages 10 and 30; and strong family history of breast or ovarian cancer.

Additional assessment tools help determine risk, and all screening decisions should be made in consultation with your doctor.

According to the American Cancer Society's guidelines, women at high risk should get an MRI in addition to a mammogram every year starting at age 30. Women at moderately increased risk, which includes having a lifetime risk of 15 to 20 percent, having a personal history of breast cancer or having "extremely dense" breasts, should talk to their doctor about adding an annual MRI screening.

1 in 5: Breast cancers may be missed by mammography, according to the National Cancer Institute.